FE validation of push-out tests: Using bolts as shear connectors

The prefabrication of concrete slabs reduces construction time and the total life cycle cost of composite steel-concrete buildings and bridge decks. Using bolts as shear connectors embedded in prefabricated concrete slabs enables reuse and easy replacement of slabs as structural members suitable for a circular economy construction concept. The results of static push-out experiments on M16 and M24 bolts, grade 8.8, are shown here. The focus is on the validation of advanced finite element (FE) modelling by experiments. Damage material models for bolt and concrete slab were used and the most realistic preloading of the bolts modelled with threads was achieved by turning the nut in the FE model. An explicit dynamic solver with mass scaling function was used for quasi-static analysis including fracture. Two failure modes obtained in experiments – bolt shear and concrete crushing – were realistically modelled by the FEA, which shows that the model is suitable for a parametric study leading to theoretical models of failure modes and slip capacity of the shear connection. Results indicate that the bolts with nuts on both sides of the steel flange can be successfully used as demountable shear connectors.